For the purpose of manufacturing a toner of a custom color that can meet the diverse needs of users, and two-colors printing or the like that can simplify an apparatus, various techniques for mixing two or more kinds of toners of which each color is different have been explored (see JP-A-Hei-6-348101, JP2004-133246 A, JP2005-316124 A, JP2004-516494 A, and the like).